Bitumen-treating agent



Patented May 23, W50

FATE? BITUMEN-TREATING AGENT tion of Delaware No Drawing. Application February 17, 1949, Serial No. 77,061

13 Claims.

This invention relates to the preparation of compositions useful in the art of road-making, and is concerned more particularly with improving the bond between aggregate and bituminous materials. More specifically, the invention pertains to the preparation of bituminous compositions containing a polyamine salt of an organosubstituted inorganic acid, whereby the bond between a bituminous substance and a wet or dry aggregate may be made stronger, firmer and more resistant to conditions tending to destroy said bond.

This application is a continuation-in-part of our co-pending application Serial No. 708,181, filed November 6, 1946 (now abandoned).

Claims directed to the polyalkylene polyamine salts of organo-substituted acids of phosphorus specifically appear in our copending application Ser. No. 77,062, filed February 17, 1949.

When employing a bituminous substance as a protective or binding material, a constant object sought in the art is the improvement of the adhesive bond between the bitumen and the material, such as aggregate, to be protected therewith or bound thereto. It is desirable to accomplish this object regardless of the type or nature of the material employed or the conditions to which the treated material may be subjected.

For example, in the construction of roadways, it is customary to apply bituminous paving materials to a suitable aggregate, reasonably available near the site of construction. Portions or all of this aggregate may be of a hydrophilic nature; that is, it is wetted by water in preference to oil. Before the ordinary bituminous paving material is applied to this type of aggregate, it is customary to dispel all of the moisture from the aggregate, otherwise a less satisfactory mix is obtained. However, even when the aggregate is dried and a good initial bond is obtained, the unavoidable contact of the bitumen-aggregate composition with normal surface water, rain water and moisture present in the subgrade gradually brings about a breakdown of the aggregate-bituminous material bond. The aggregate is gradually wetted by the water, and the bituminous substance no longer holds the aggregate together, as a result of which a breakdown of the roadway occurs.

A number of substances, known as anti-stripping agents, have been proposed for the purpose of strengthening the bond between hydrophilic aggregate and bituminous substances. These agents are incorporated into the bituminous substance and/or the aggregate. However, many of these substances are relatively expensive for use in the large quantities required in new roadway construction or in roadway repair work. Other substances which are more readily available for this purpose and are relatively inexpensive are nevertheless unsatisfactory for long-term use due either to decomposition of the anti-stripping agent itself or the tendency thereof to cause emulsification of water into the surface.

It is an object of this invention to provide a means of forming a lasting bond between bituminous substances and mineral aggregate.

It is a further object of this invention to provide bituminous compositions capable of adhering firmly to moist mineral aggregate.

It is still a further object of this invention to provide bituminous compositions which will continue to adhere firmly to mineral aggregate.

It is another obJect of this invention to provide a means of treating mineral aggregate so that a lasting bond may be obtained between bituminous substances and the treated mineral aggregate.

It is also an object of this invention to provide a relatively inexpensive means for providing a lasting bond between bituminous substances and mineral aggregate.

Further and other pertinent objects of this ininvention will be apparent from the following description of the invention.

We have found that the foregoing objects of the invention may be achieved by bringing together mineral aggregate and a bituminous substance in the presence of a polyamine salt of an organo-substituted inorganic acid. Aggregate and/or bituminous substances treated with a polyamine salt of an organo-substituted inorganic acid have been found capable of forming paving mixtures of aggregate and a bituminous substance characterized by a strong adhesive bond between bituminous substance and aggregate. We have further found that this bond may be obtained with a wide variety of wet or dry aggregate, and that paving mixtures formed in accordance with our invention exhibit superior anti-stripping qualities.

The polyamine salts contemplated by the present invention are such as are formed by the reaction of an organo-substituted inorganic acid, hereinafter to be more fully described, and a relatively cation surface inactive polyamine, having at least two amino groups, and which may also include imino groups, at least one of which amino or imino groups is capable of forming salts with acidic materials.

Polyamines comprehended by the invention include polyamines having at least two terminal amino groups, which because of the terminal groups, are essentially hydrophilic and are ordinarily considered to be relatively cation surface inactive materials, for example, ethylene diamine; polyamines which, although not possessing terminal amino groups, have terminal carbon chains with fewer than 12 carbon atoms contained therein, that is, terminal chains having a carbon content below the minimum ordinarily considered to be necessary in such chains in order to impart surface activity to the molecule, for example, 2,5-diamino dodecane; and substantially cation surface inactive polyalkylene polyamines, such as tetraethylene pentamine.

In general, polyamines included within the scope of the invention may vary from polyamines containing two carbon atoms to polyalkylene polyamines containing 60 or more carbon atoms. Suitable polyamines are such that when formed into a salt with the organo-substituted inorganic acid, the salt is dispersed in the bituminous material, whether or not true solutions or mere stable dispersions of the salt and the bituminous materials are formed. Polyamine salts of organo-substituted inorganic acids containing about 4 and, preferably, 8, to about 26 carbon atoms in the salt as a whole, such as diethylene triamine wood turpentine sulfate and diethylene triamine lauryl phosphate, have been found particularly advantageous to use, since they may be formed from readily available materials and give good results. However, salts containing a greater number of carbon atoms, for example, diethylene triamine asphalt sulfonate, are also contemplated by the invention.

We are aware that lipophilic surface active amines have heretofore been proposed as bitumen-treating agents, as shown, for example, in U. S. Patent 2,370,386, and as-shown by the use of certain fatty amines. The effectiveness of such materials has been thought due to the presence of a lipophilic group capable of solubilizing in the oil, and a polar amino group capable of reacting with or being adsorbed into the surface of the aggregate, thus providing a bridge between the dissimilar oil and aggregate surfaces. For this reason, the amine selected in the art has been a surface active lipophilic material. In accordance with our invention, it has been found that readily available and inexpensive substantially surface inactive polyamines may be employed with a non-amidizing organo inorganic acid to produce, contrary to expectations, a stable and highly polar material of superior efiectlveness.

Specific examples of polyamines are trimethylene diamine, pentamethylene diamine, phenylene diamine, tolylene diamine, histamine, methyl guanidine, triethylene tetramine, diethylene triamine, tetraethylene pentamine, guanidine, diguanide, N-methylamino aniline, urea and thinurea, decamethylene diamine, octadecyl diamine,

hexamethyl trimethyl triamine, ethylene diamine, propylene diamine, etc.

The organo-substituted inorganic acids contemplated by the invention are acid-reacting materials capable of forming a salt with the polyamines. These materials include acid-reacting organo-substituted inorganic acids, such as the acids of a, weak acid-forming element, for example, boron or silicon, and organo-substituted acids of strong acid-forming elements, for example, phosphorus and sulfur. More preferably employed, however, are the organo-substituted acids of the strong acid-forming elements, such as sulfur, phosphorus and nitrogen. I

In addition, the organo-substituted inorganic acids are such as contain at least two carbon atoms, and at least one ionizable hydrogen capable of reacting with the polyamines to form the salt. In general, these materials include compounds characterized by a direct carbon-toacid-forming element bond, for example, a sulfonic acid; and compounds having the carbon and acid-forming element linked to an intermediate atom such as oxygen, for example, the monoesters of sulfuric acid.

As examples of general types of suitable inorganic acids containing an organic substituent may be mentioned acids Of trivalent and pentavalent phosphorus; acids of tetravalent and hexavalent sulfur; acids of boron; carbonic acids; silicic acids, and acids of arsenic.

More specific types of the organo-substituted inorganic acids are the monoesters of sulfuric acid, the monoand diesters of phosphorus, the monoand diesters of phosphoric, orthoboric, arsonic, arsenious, arsenic, and orthocarbonic acids; phosphonous, phosphonic, sulfonic, sulfinous, sulfinic, boronic, arsinic, arsonic, stibonic and arsinous acids; such esters of the latter materials as do not deprive the compound of its acid-reacting nature or its ability to form salts with the polyamines, for example, the monoester of phosphonic acid. The sulfur derivatives of the foregoing materials to yield thio compounds are not precluded, for example, monoand dithioesters of phosphoric acid.

The organic substituent of the inorganic acid may be alkyl groups, saturated, unsaturated or substituted; alkaryl, aryl, arylalkyl, cyclic nonbenzenoid radicals; and oxygen-containing radicals, such as those in which the hydrogen of a hydroxyl group has been replaced by esterification, etherification, etc. The nature of these organic radicals is such that the salt of the polyamine and. organo-substituted acid is soluble in the bituminous substance or, in the absence of the formation of a true solution, may be stably dispersed in the bituminous material.

Specific examples of organo-substituted inorganic acids which may be employed in accordance with the invention are: monolauryl sulfuric acid, palmito glyceryl sulfuric acid, wood turpentine sulfuric acid, monoethyl phosphoric acid; monoand didodecyl, monoand dicetylplenyl, monoand tertradecyl, monoand dioctadecyl, monoand ditetradecylphenyl, monoand dioctadecylphenyl esters of phosphorus and phosphoric acids; monododecyl, mononaphthenyl, monoamylphenyl, mono-tetradecylphenyl boric, xanthic and dithiolcarbonic acids; ethyl, propyl, butyl, amyl, hexyl, octyl, decyl, dodecyl, tetradecyl compounds of phosphonous, phosphonic, arsonic, arsonous, sulfinous, sulfinic acids; dodecane sulfonic, p-toluene sulfonic, octadecane sulfonic, tetradecane sulfonic, dodecyl 5 benzene sulionic, asphalt sulfonic acids; hexyl, octyl, decyl, tetradecyl, and dodecyl compounds of arsonous acid; monodecyl, monododecyl, monocetyl propylarsonic acid; hexyl, octyl, decyl, tetradecyl, octadecyl esters of phosphonous and phosphonic acids; the reaction product obtained by nitrating a petroleum resin to form R-NO2, wherein R refers to the petroleum resin, and which nitro petroleum resin tautomerizes to form a nitroxy acid (R- -CH=N capable of reacting with the polyamine to form the salt.

The method of incorporation of the polyamine salt contemplated by the invention in mixtures of aggregate and bituminous substance is not critical. Thus pre-formed salt of polyamine and organo-substituted inorganic acid may be added to the bituminous substance and/or to the aggregate prior to admixture of the two; or the salt may be formed in situ in either the aggregate or the bituminous substance or both; or the saltforming elements of polyamine and acid may be added separately or combined in physical mixtures to either or both bituminous substance and aggregate, in which event it is believed that the salt product is formed upon the migration of the salt-forming elements to the interface of aggregate and bituminous substance. By polyamine salt, therefore, it is intended to include the reaction product of the polyamine and organosubstituted inorganic acid, as well as mere physical mixtures of the two salt forming elements.

According to the preferred embodiment of the invention, the salt is prepared prior to the incorporation thereof in the bituminous substance. The salt may be obtained by mixing the polyamine and acid, preferably in the presence of a diluent or solvent, at ambient temperatures or at elevated temperatures to expedite admixture and reaction, but below decomposition temperatures of the reactants and of the final salt product. Upon completion of the reaction, the resulting product may be added as such or after removal of part or all of the diluent or solvent or in otherwise purified form, for example, the salt obtained after subjection of the reaction products to purification methods well known in the art, such as distillation or solvent extraction, etc.

In the preparation of the salt, the polyamine and the acidic substance need not be present in stoichiometric proportions, an excess of one or the other being permissible. In general, satisfactory materials have been prepared by employing a mol ratio of polyamine to organo-substituted inorganic acid varying from about 1:5 to about 5:1.

In practicing this invention, the polyamine salt of an organo-substituted inorganic acid may be added to the bituminous substance before the latter is mixed with the aggregate or the aggregate may be separately treated with the polyamine salt. In the event the polyamine salt is mixed first with the bituminous substance, it is sufiicient merely to mix the two together with such heating and agitation as may be necessary to produce a homogenous blend. When the aggregate is separately treated with the polyamine salt, the latter may be mixed with the aggregate as such, or the polyamine salt may be dissolved in a solvent, for example, kerosene, before being mixed with the aggregate. It is also possible to mix the aggregate, the polyamine salt and the bituminous substance simultaneously.

In any case, the polyamine salt need be used in only small amounts. Amounts ranging from about 0.05 to about 10 per cent by weight, preferably 0.1 to 2 per cent, of the bituminous substance when the polyamine salt is added to the bituminous substance have been found satisfactory; or about 0.001 per cent to about 1 per cent, preferably 0.01 to about 0.5 per cent, of the aggregate when the aggregate is treated separately with the polyamine salt.

The bituminous materials that may be employed in accordance with the invention are those employed in the construction and repair of roads, and are normally solid, semi-solid, or viscous liquids at ordinary atmospheric temperatures. Examples of suitable bituminous substances or bitumens are petroleum or native asphalt; pyrogenous distillates, such as oil-gas tar, coal tar; pyrogenous residues, such as blown asphalts, sludge asphalts, pressure tars, tar pitch; pyrobitumens, etc. In addition, mixtures of the foregoing materials, as well as mixtures or solutions of the aforesaid materi ls with solvents, such as naphtha, kerosene and stove oils, to give so-called liquid asphalts are also contemplated by the invention.

Of the foregoing materials, petroleum asphalt produced by steam-refining, b air-blowing, by solvent extraction methods or by a combination of such methods, and having penetration values of about 30 to about 400 according to A. S. T. M. D-5-25 method, is most advantageously used. Also, but less desirably, oil-in-water type emulsions of these and other bituminous materials may be used. Such emulsions can be prepared by methods well known in the art; and the emulsions may be of the quick-breaking or penetration type or more stable type emulsions, such as slow-breaking or a mixing type emulsion.

When the bituminous substance is present in the continuous phase, as in unemulsified asphalts,

. cut-backs and road oils, it is preferred to add the polyamine salt to the bituminous substance. When the bituminous substance is emulsified in water, the polyamine salt is preferably added to the aggregate.

The following examples illustrate the preparation of salts contemplated by the invention.

Example I .-Preparatz'on of diethylene-triamineethyl phosphate One part by weight of ethyl phosphoric acid was reacted at room temperature with ten parts by weight of a 70% solution of diethylene triamine in water to form a solution of diethylene-triamine-ethyl phosphate in water.

Example II.Preparation of ethylene-(imminelauryl phosphate Nine parts by weight of lauryl phosphoric acid were reacted at room temperature with one part by weight of a 70% solution of diethylene triamine in water to form a heavy paste of diethylene-triamine-lauryl phosphate and water.

Example III .P7eparati0n of diethylene-triamine-cetyl phenyl thiophosphate Two parts by weight of cetyl phenyl thiophosphoric acid were reacted with one part by weight of a 70% solution of diethylene triamine in water to form a viscous liquid constituting diethylene triamine cetyl phenyl thiophosphate and water.

Example IV.Pre'parati0n of decamethulenediamz'ne-wood turpentine sulfate This wood turpentine sulfate is a partially purified by-product of the papenmanutacturing industry.

tonated lignin may be used. as is, in the carbon tetrachloride solution,

(b) One part by weight or the lignin sultonic acid so produced was reacted with ten parts by The benweight of a 70% water solution of diethylene tri- Two parts by weight of wood turpentine sulamine by stirring the two components together rate were mixed with one part by weight of a at room temperature to form a paste of dieth- 70% solution of decamethylene diamine 1:111 water ylene triamine lignin suiionate and water. form a semi'gel of decamethylene amine Example VIL-Preparation of a petroleum resin wood turpentine sulfate and water nitrate and poluamine salt of same Example 2 52223222 ;:gfi'gggi m (a) Three parts by weight of petroleum resin were treated with 2 parts by weight of fuming (a) 500 grams of a 200 penetration (A. S. T. M. nitric acid (with constant agitation and cooling D-5-25 method) California steam-refined asphalt to keep the temperature at room temperature) were dissolved in 1600 grams of carbon tetraohloto form the petroleum resin nitrate. ride. To this solution was slowly added 85 grams (21) One part by weight of the petroleum resin of 95% sulfuric acid with continuous agitation nitrate so prepared was treated with five parts by and cooling. After this reaction mix had been weight of a 70% water solution of diethylene trileft standing for 48 hours, the reaction mixture amine by stirring the two components together was shaken vigorously with 1500 grams of water. at room temperature to form a mixture of di- The water layer was then drawn off. The reacethylene triamine nitrated petroleum resin salt tion mixture was shaken two more times with and water. 1500 grams of water each time, followed by a like The petroleum resin was obtained from a Caliperiod of settling and the withdrawal 01' the 25 fornia steam-refined asphalt by the following water, At this point, the carbon tetrachloride procedure. The asphalt was treated with petromay be evaporated from the sul o d. asphalt leum ether to precipitate the asphaltene fraction. (asphalt sulfonic acid) in vacuo, using a mini- The petroleum ether extract (which contained mum of heat, or the sulfonated asphalt may be the petroleum resin fraction) was then treated used, as is, the carbon tetrachloride solution. 3" with clay to separate the petroleum resin from (b) Two parts by weight of the above asphalt other petroleum ether soluble fractions. The sulfonic acid were then reacted with one part by petroleum resin was extracted from the clay with weight of a 70% water solution of diethylene tria mixture of 1 part by volume of benzene and 1 amine at room temperature to form a viscous liqpart by volume of 190-proof ethanol, 111d 0 p p e- P a e a d zene-ethanol solvent was then removed from the water. petroleum resin by distillation. Example VI.Preparation of lignin sulfonic acid The followmg Table I illustrates t eflectlve' and polyamme salt of same ness of the polyamine salts of the invention on the retention of a film of asphalt on several types (a) 500 grams of a purified lignin (as described 40 of aggregates. The film retention test used was a by Plenguianr Chem- 32, 1399-1400 modification of the standard Nicholson film strip- (1940) and the Umted States Patent 2,228,976) ping test described in the Proceedings of weredispersed in 1600 grams of carbon tetraphalt Paving Technologists, January 1932, page chloride. To this dispersion was slowly added 85 In the test used, test samples of appmxi rams of 95% sulfuric acid with continuous agi- 45 mately 100 g. of the mixture of aggregate tatlon and 1 After thls reacmm had tuminous substance and anti-stripping agent were been left standing for 48 hours, the reaction mixallowed to cure in an Oven at for 24 hours. ture was shaken vigorously with 1500 grams of Following the curing period about 50 of the waterj Water layer was then drawn cured mixture were placed in a flask partially The reaction mixture was shaken two more times 50 fined with distilled water at The flask with 1500 grams of water each time, followed by was stoppered and placed in a frame which was a period Of settling and the withdrawal Of t t in a water t 1400 F After the water. At this point, the carbon tetrachloride utes of rotation, the appearance' of the mixture may be evaporated j the sulfgnatedhngmn was reported in terms of estimated area that rein vacuo, mmnnum of hea or t e mained coated at the conclusion of the test. Conventionally, any aggregate retainin less than per cent of film is considered to have failed.

Table I Per Cent Film Retention on Aggregates Test Oil Limestone Silim Rhyoli'te A 100% Medium Curing (MC-2) Asphalt Cut-B 70 30 40-50 B 99% Medium Curing (MC-2) Asphalt Cut-Back plus 1% of the water solution of diethylenetriamineethyl phosphate of Example 35 95 C 99% Medium Curing (MC-2) Asphalt Cut-Back plus 1% of the ethylene diamine lauryl phosiiate paste of Example II 100 95 95 D 99 0 Medium Curing (MC-2) Asphalt Cut-Back lus 1% of the viscous methylene-triaminecctyl phenyl thiopiiosphate liquid of Example II 80 95 95 E 99% Medium Curing (MC-2) Asphalt Cut-Back plus 1% of the decamethylene-diamine wood turpentine sulfate gel of Example IV. 80 90 F 99% Medium Curing (MC-2) Asphalt Cut-Back plus 1% of the viscous propylene-diamineasphalt-sulionate liquid of Exam 1e V 80 100 90 G 99% Medium Curing (MC-2) Asp alt Cut-Back plus 1% of the diethy -ne-triamme-ligninsulfonate paste of Example V 80-90 100 -100 H 99% Medium Curing (MC-2) Asphalt Cut-Back plus 1% of the diethylene-triamme-peti-oleum resin nitrate salt water mix of Example V 90 05 95 Example VIII Limestone Silica Rhyolite Per cent Per cent Per cent Example IX About 60 g. of starch and 31 g. of boric acid were stirred together with gentle heating until the mass fused into a boric acid-starch complex.

About 0.33 g. of this complex was mixed with about 0.77 g. of hexaethylene heptamine, and the resulting mixture added to 99 g. of an MC-2 liquid asphalt. Film-stripping results after subjection of the treated liquid asphalt to the modified Nicholson film-stripping test above described were as follows:

Limestone Silica Rhyolite Per cent Per cent Per cent 80 9O 90 Example X (a) A stock of crude eocene phosphonic acids was prepared according to the process described in the Jensen and Clayton co-pending application, filed December 13, 1946, Serial No. 716,182. That is, about 144 pounds of eocene (a petroleum fraction of aniline point 161.6 and a boiling range of about 325-500" F.) were mixed with phosphorus trichloride. Dry oxygen was bubbled through the mixture until the temperature of the reaction mixture started to drop. A major portion of the POCls formed as a by-product of the reaction was distilled oil under vacuum, and then 100 pounds of cracked ice added to hydrolyze the product. After thorough agitation, the water layer was drawn ofi, the reaction mixture washed twice with water and the resultant crude phosphonic acid stock used as an anti-stripping ingredient. The active acid content was determined to be about 20 per cent of the reaction product.

(b) About 0.87 g. of the eocene phosphonic acid and 0.13 g. of diethylene triamine (anhydrous) was added to 99 g. of liquid asphalt. Anti-stripping results of the so-treated liquid asphalt were as follows:

Limestone Silica l Rhyolite Per cent Per cent Per cent agents. For example, Dohse et al. Patent No. 2,191,295 discloses as anti-stripping agents the salts of polyethylene amines, and certain derivatives thereof, formed with hydrochloric, sulfuric, tartaric, acetic, citric or phosphoric acids. Our salt materials, however, containing an organic substituent in the acid portion of the molecule. have been found to give unexpectedly superior results.

These results are illustrated by the test data hereinbelow appearing in Table II, which data were obtained from a comparison oi. polyamine salts of unsubstituted acids, as disclosed by the aforesaid patent, with the polyamine salts of the organo-substituted inorganic acids of the present invention. Per cent of film retention was determined according to the modifletd Nicholson filmstripping test hereinabove described.

Table II Percent Film Retention Percent Additive MC-2 Road Oil Limestone Silica Rhyolite l 0% Blank 1 part 1% 1 part H01"--- diethylene trimin 1 part H1504 1 part H3PO4 1% 1 part dietliylene triamino 1 part cetyj phos- 17 phone ac1d 1 part dietliylene triamin From the foregoing data, it will be noted that as regards the easily coated limestone, the unsubstituted phosphoric acid was only 60 per cent effective, whereas the substituted phosphoric acid was 100 per cent effective. With silicia aggregate, the unsubstituted phosphoric acid was only 60 per cent effective, while our substituted phosphoric acid was 100 per cent eflective. When the tests were conducted with Rhyolite, an aggregate normally quite diflicult to coat securely, the combination of diethylene triainlne and the unsubstituted phosphoric acid of test 4 was only 20 per cent efiective, whereas, as shown in test 5, when using the organo-substituted acid, the coat ing was 100 per cent effective. A similar improvement is shown in the use of organo-substituted phosphoric acid over the unsubstituted hydrochloric and sulfuric acids.

The salts herein contemplated need not be added to the bitumin and/or to the aggregate in pure form. For example, in the event a diluent, for example, kerosene, for any or both of the salt-forming reactants is employed, upon formation of the salt the diluent need not be removed from the reaction product prior to its use with the bitumen, suflicient amount of the diluted salt being used as to give the calculated desired amount of salt in the finished product.

Conversely it is often advantageous to prepare the salts in concentrate form, and in this form incorporate into either bitumen or aggregate or both in the desired amounts. Such a procedure has the advantages of providing for more intimate admixture of the salt and the material to be treated. Concentrates of hydrocarbon oil, such as kerosene or naphtha, containing from about 15 per cent to as much 50 per cent by weight of the salt are quite satisfactory. In addition to kerosene, other hydrocarbon diluents or solvents may be employed in the preparation ll of the concentrate. Such materials include mineral oils, lubricating oils and the like. Examples of other diluents are bituminous substances such as the so-called liquid asphalts hereinabove mentioned.

The term polyalkylene polyamine" is intended to include ethylene diamine, propylene diamine, and higher similar unpolymerized compounds, since the alkylene group of such compounds may be considered as containing more than one alkylene methylene group (CHa-), and hence may be considered as' being polyalkylene polyamines.

Obviously, many modifications and variations oi the invention, as hereinabove set forth, may be made without departing from the spirit and scope-thereof, and only such limitations are to be imposed as are indicated in the appended claims.

We claim:

1. A bituminous composition having superior anti-stripping properties consisting essentially of a bitumen normally possessing stripping tendencies and an amount suflicient substantially to lessen stripping of said bitumen of the salt of a polyalkylene polyamine and an organo-substituted inorganic acid having at least two carbon atoms and at least one ionizable hydrogen.

2. A composition substantially as described in claim 1, wherein the bitumen is asphalt.

. 3. A composition substantially as described in claim 1, wherein the salt is present in an amount of about 0.05 to about by weight of the bitumen.

4. A composition substantially as described in claim 1, wherein the salt is present in an amount of 0.1 to about 2% by weight of the bitumen.

5. A bituminous composition substantially as described in claim 1, wherein the organo-substituted inorganic acid is characterized by a direct carbon-to-acid-forming-element bond.

6. A bituminous composition having superior anti-stripping properties consisting essentially of a bitumen normally possessing stripping tendencies and an amount suflicient substantially to lessen stripping of said bitumen of the salt of a polyalkylene polyamine and an organo-substituted inorganic acid having at least one ionizable hydrogen and at least two carbon atoms, said 12 carbon atoms being linked to the acid-forming eliementsof said acid through an intermediate a cm.

7. A bituminous composition substantially as described in claim 5 wherein the intermediate carbon atom is oxygen.

8. A composition substantially as described in claim 1 wherein the inorganic acid is an acid of sulphur.

9. A composition substantially as described in claim 1, wherein the inorganic acid is an acid of boron.

10. A composition substantially as described in claim 1 wherein the inorganic acid is nitric ac d.

11. A bituminous road construction composition consisting essentially in intimate combination, of mineral aggregate, a bituminous substance-and about 0.05 to 10% by weight of the bituminous substance 01 the salt of a polyalkylene polyamine and an organo-substituted inorganic acid having at least two carbon atoms and at least one ionizable hydrogen.

12. A bituminous road composition substantially as described in claim 11, wherein the salt is present in an amount of about 0.1 to about 2% by weight of the bitumen.

13. A bituminous composition substantially as described in claim 11, wherein the bituminous substance is asphalt.

VAUGHN R. SMITH. DON E. STEVENS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,127,495 'Iulleners Aug. 23, 1938 2,191,295 Dohse et al Feb. 20, 1940 2,236,515 Cahn et a1. Apr. 1, 1941 2,345,388 Ericks et a1. Mar. 28, 1944 2,370,386 Anderson et a1. Feb. 27, 1945 2,378,235 Miles June 12, 1945 2,387,537 Smith et a1 Oct. 23, 1945 2,397,667 Kaiser et al. Apr. 2, 1946 2,409,344 Davis Oct. 15, 1946 

1. A BITUMINOUS COMPOSITION HAVING SUPERIOR ANTI-STRIPPING PROPERTIES CONSISTING ESSENTIALLY OF A BITUMEN NORMALLY POSSESSING STRIPPING TENDENCIES AND AN AMOUNT SUFFICIENT SUBSTANTIALLY TO LESSEN STRIPPING OF SAID BITUMEN OF THE SALT OF A POLYALKYLENE POLYAMINE AND AN ORGANO-SUBSTITUTED INORGANIC ACID HAVING AT LEAST TWO CARBON ATOMS AND AT LEAST ONE IONIZABLE HYDROGEN. 